Circuit Substrate, Electrowetting Device Using the Same, and Control Circuit

This application claims the benefit of priority to Japanese Patent Application Number 2025-044055 filed on Nov. 19, 2024. The entire contents of the above-identified application are hereby incorporated by reference.

The disclosure relates to a circuit substrate, an electrowetting device using the circuit substrate, and a control circuit.

JP 2003-228299 A discloses a method of determining whether a display device is non-defective. Further, JP 2020-42261 A discloses an electrowetting on dielectric device (EWOD) using an active matrix substrate.

For example, a circuit substrate (active matrix substrate) used in an electrowetting device has a problem that whether the circuit substrate is non-defective cannot be determined before the circuit substrate is incorporated into a target device. Further, since an operation cannot be confirmed unless a conductive liquid is injected between the circuit substrate and a counter substrate, even when a current leak failure occurs during actual use, the current leak failure cannot be detected.

A circuit substrate according to an aspect of the disclosure is a circuit substrate including a control circuit including an input transistor, an output transistor, and an output node, in which one conduction terminal of the input transistor is connected to a control terminal of the output transistor, one conduction terminal of the output transistor is connected to the output node, and the circuit substrate includes an inspection circuit element connected to the output node.

A circuit substrate used in an electrowetting device according to an aspect of the disclosure includes a control circuit including an input transistor, an output transistor, and an output node, in which in the control circuit, a current corresponding to input to the one conduction terminal of the input transistor flows to the output node via the output transistor, and the control circuit includes an inspection circuit element connected to the output node.

Electrowetting is a phenomenon in which, when an electric field is applied to a droplet (conductive liquid), which is arranged on a water-repellent dielectric layer provided on an electrode, a contact angle of the droplet with respect to the dielectric layer is changed. Through use of the electrowetting, for example, a fine droplet can be manipulated.

According to an aspect of the disclosure, whether a circuit substrate is non-defective can be determined before the circuit substrate is incorporated into the electrowetting device. In addition, even when a defect occurs after the circuit substrate is incorporated into the electrowetting device, the defect can be detected.

1 FIG. 1 FIG. 1 2 2 1 2 7 8 8 1 1 7 1 2 8 8 1 8 7 8 8 8 1 1 8 2 1 1 2 a a c a a b c a a c a b is a circuit diagram illustrating a configuration example of a circuit substrate and an electrowetting device including the circuit substrate according to the present embodiment. As illustrated in, a circuit substrateaccording to the present embodiment includes a control circuitincluding an input transistor T, an output transistor T, a holding capacitor Cs, and an inspection circuit element Td. The control circuitincludes a first terminal, a second terminal, a third terminal, and an output node N. The inspection circuit element Td may include at least one of a wiring line, a resistor, a capacitor, or a transistor. One of two conduction terminals of the output transistor Tis connected to the first terminal, and the other is connected to the output node N. One of two conduction terminals of the input transistor Tis connected to the second terminal, the other conduction terminalis connected to a control terminal of the output transistor T, and the control terminal is connected to the third terminal. When a power supply voltage is input to the first terminal, a data signal is input to the second terminal, and a scanning signal is input to the third terminal, a current corresponding to the magnitude of the data signal input to the second terminalflows to the output node Nvia the output transistor T. The inspection circuit element Td and the holding capacitor Cs are connected to the other conduction terminalof the input transistor Tand the output node N. The circuit substrateincludes a control circuit group including a plurality of the control circuits.

6 1 2 3 1 4 15 5 1 4 6 6 8 8 1 7 15 7 5 1 1 3 5 3 a c a a An electrowetting deviceincludes the circuit substrateincluding the plurality of control circuits, element electrodes(e.g., anodes) connected to output nodes N, a counter substrateincluding a counter electrode(e.g., a cathode), and conductive liquidsinjected between the circuit substrateand the counter substrate. When used as the electrowetting device, all or some of the inspection circuit elements Td may be removed, or the inspection circuit element Td may be left. In the electrowetting device, by supplying the data signal to the second terminalwhile applying the on voltage to the third terminal, a voltage corresponding to the data signal is written to the control terminal of the output transistor T. That is, by supplying a high potential voltage to the first terminaland a low potential voltage to the counter electrode, a current corresponding to the data signal is applied from the first terminalto the conductive liquidvia the output transistor T, the output node N, and the element electrode. Accordingly, an electrical field corresponding to the data signal is generated, and an apparent contact angle of the droplet (conductive liquid) can be controlled according to the magnitude of the electrical field. By setting the magnitude of the electrical field for each of a plurality of the element electrodes, a manipulation of the droplet can be controlled.

2 FIG. 2 FIG. 1 2 FIGS.and 1 FIG. 1 2 2 1 2 7 8 8 7 1 1 2 1 2 a a c b is a configuration example of another circuit substrate and an electrowetting device including another circuit substrate according to the present embodiment. As illustrated in, the circuit substrateaccording to the present embodiment includes the control circuitincluding the input transistor T, the output transistor T, the holding capacitor Cs, and the inspection circuit element Td. The control circuitincludes the first terminal, the second terminal, the third terminal, a fourth terminaland the output node N. The output transistor T, the input transistor T, and the holding capacitor Cs are connected to the same terminals as those in, and perform the same operation as that in. The circuit substrateincludes a control circuit group including the plurality of control circuits.

7 1 b The inspection circuit element Td may include at least one of a resistor, a capacitor, or a transistor, and is connected to the fourth terminal(monitoring terminal) and the output node N.

6 1 5 4 15 1 FIG. The electrowetting deviceincludes a circuit substrate, a conductive liquidand a counter substrateincluding a counter electrode(e.g., a cathode) and operates in a similar manner as in.

3 FIG. 4 FIG. 5 FIG. 6 FIG. 3 FIG. 4 FIG. 6 1 3 4 1 5 1 4 4 15 3 30 5 1 4 5 1 4 is a cross-sectional view of the electrowetting device.is an overall view of the circuit substrate.is a plan view of a glass substrate.is a schematic cross-sectional view of the glass substrate. As illustrated in, the electrowetting deviceincludes the circuit substrateincluding the element electrodes, the counter substratefacing the circuit substrate, and the conductive liquiddisposed between the circuit substrateand the counter substrate. As illustrated in, the counter substrateincludes a cathode electrode(counter electrode) facing the element electrodes, and injection portsfor injecting the conductive liquids. An air layer may be formed between the circuit substrateand the counter substrate, or a non-conductive liquid which is not mixed with the conductive liquidmay fill a space between the circuit substrateand the counter substrate.

8 2 31 1 5 a When a current corresponding to the data signal to the second terminalof the control circuitis applied to an element electrodevia the output node N, an electrical field is generated, and a contact angle of the droplet (conductive liquid) changes, thereby enabling the droplet to be manipulated.

4 5 FIGS.and 1 10 12 13 14 12 10 10 14 13 16 As illustrated in, the circuit substrateincludes a glass substrate, semiconductor chips, chip on film (COF), and a printed circuit substrate (PCB). The semiconductor chipis mounted on the glass substrateby chip on glass (COG). The glass substrateand the PCBare connected to each other via the COFand a connector.

6 FIG. 10 2 3 31 12 13 As illustrated in, on the upper surface of the glass substrate, wiring lines and thin film transistors (TFTs) are formed, and the control circuitsand the element electrodesare arranged in an array. Further, connection terminalsfor mounting the semiconductor chipsor the COFare formed.

5 As the conductive liquid, an ionic liquid, a polar liquid, or the like is used. As the conductive liquid, for example, water, electrolytic solution (electrolyte water solution), alcohols, and various types of ionic liquids may be used. As examples of such liquids, a whole blood specimen, a bacterial cell suspension, a protein or antibody solution, and various types of buffer solutions are exemplified. When used in a device (FET sensor, biosensor, etc.) that actively controls an electrochemical reaction of the ionic liquid by current driving, the ionic liquid may be an acid solution such as a sulfuric acid, a hydrochloric acid, a nitric acid, or the like, and may further include a metal ion. In the case of being used in a device (cell potential sensor or the like) that actively reads an electrical field in a solution from the conductive liquid, an electrolytic solution suitable for the application may be used.

1 6 FIG. The circuit substrateillustrated incan be manufactured, for example, by the following process.

10 First, SiO/SiNx films of a base coat film BC having thicknesses of 100 nm/100 nm, respectively, is formed on the glass substrateby a chemical vapor deposition (CVD) apparatus, Si of a silicon film SC having a thickness of 40 nm is formed thereon, and then dehydrogenation annealing and laser annealing are performed to pattern the silicon film SC. After SiO of a gate insulating film GI having a thickness of 100 nm is formed on the silicon film SC by a CVD apparatus, an MoW film of a gate electrode GE having a thickness of 300 nm is formed by a sputtering apparatus, and the gate electrode GE is patterned.

1 1 Then, after the silicon film SC is subjected to a lightly doped drain (LDD) doping process and a heavily doped drain (ND) doping process, SiO/SiNx films of a first interlayer insulating layer ILDhaving thicknesses of 700 nm/200 nm, respectively, is formed on the gate electrode GE by a CVD apparatus, and after contact holes for connection are formed in the first interlayer insulating layer ILD, Ti/Al/Ti films of a source electrode SE having thicknesses of 30 nm/300 nm/20 nm, respectively, is formed by a sputtering apparatus, and the source electrode SE is patterned.

1 1 3 3 Subsequently, a SiNx film of a first passivation layer Pahaving a thickness of 300 nm is formed on the source electrode SE by a CVD apparatus, and after contact holes are formed in the first passivation layer Pa, Ti/Al/Ti films of a first metal layer Mhaving thicknesses of 100 nm/600 nm/20 nm, respectively, is formed by a sputtering apparatus, and the first metal layer Mis patterned.

2 3 Thereafter, SiO/siNx films of a second passivation layer Pahaving thicknesses of 400 nm/150 nm, respectively, are formed on the first metal layer Mby a CVD apparatus, and a flattened layer PLN having a thickness of 2 μm is formed thereon and patterned by photolithography. The flattened layer PLN may be made of an acrylic or polyimide resin material, and preferably has photosensitivity.

3 3 2 Then, a SiNx film of a third passivation layer Pahaving a thickness of 100 nm is formed on the flattened layer PLN by a CVD apparatus, and a contact hole is formed in the third passivation layer Paand the second passivation layer Pa.

3 3 Subsequently, a Ti film of the element electrodehaving a thickness of 300 nm is formed on the third passivation layer Paby a sputtering apparatus and patterned.

2 3 31 31 31 Thereafter, a SiNx film of a second interlayer insulating layer IDLhaving a thickness of 100 nm is formed on the element electrode, and a SiNx film of the connection terminalis removed. Subsequently, a water-repellent layer WR is formed. The water-repellent layer WR is formed by a fluorine-based resin layer having a functional group at a terminal and having a thickness from 30 nm to 100 nm. Through use of a fluorine-based resin solution (including a fluorine-based resin solvent), the fluorine-based resin layer may be formed by a publicly known method. In order to improve removal of the solvent and/or stability of the fluorine-based resin, heat treatment at approximately from 170° C. to 200° C. is preferably performed. Further, before the fluorine-based resin layer is formed, a silane coupling agent treatment or a fluorine-based primer treatment may be processed. It is preferable that the water-repellent layer WR is not formed in a region where an adhesive for bonding the counter substrate is formed or on the connection terminal. For example, after the fluorine-based resin film is formed on the entire surface of the substrate, an opening may be formed at the sealing portion and the connection terminalby a photolithography process.

3 3 3 The gate electrode GE, the source electrode SE, the first metal layer M, and the element electrodemay be made of any combination of Mo, Al, Ti, and W, or alloys thereof. The element electrodemay be made of a conductive transparent material such as ITO or IZO.

The base coat film BC has a layered structure of the SiO/SiNx films, but may have a single layer structure of a SiO film or a SiNx film.

Although low temperature polycrystalline silicon (LTPS) is used for the TFT, both P-type and N-type TFTs may be used, or a circuit configuration using one of P-type and N-type TFTs may be employed. The semiconductor layer may be made of an oxide semiconductor (for example, indium gallium zinc oxide) or a-Si.

7 FIG. is a circuit diagram of an equivalent circuit of a control circuit provided on a circuit substrate according to a first embodiment. Constituent elements similar to the constituent elements described above are denoted by the same reference signs and numerals, and detailed descriptions thereof will not be repeated.

1 2 2 2 1 2 1 The circuit substrateincludes the control circuit. The control circuitincludes the input transistor T, the output transistor T, the holding capacitor Cs, and an inspection wiring line Ltest. The control circuitfurther includes a first terminal Tp, a second terminal Tdata, a third terminal Tsel, and the output node N.

1 1 2 8 9 1 9 1 1 8 1 b b One of two conduction terminals of the output transistor Tis connected to the first terminal Tp, and the other is connected to the output node N. One of the two conduction terminals of the input transistor Tis connected to the second terminal Tdata, the other conduction terminalis connected to a control terminalof the output transistor T, and a control terminal is connected to the third terminal Tsel. One terminal of the holding capacitor Cs is connected to the control terminalof the output transistor Tand the other terminal is connected to the output node N. The inspection wiring line Ltest is connected to the conduction terminaland the output node N.

2 1 1 2 1 2 When providing the inspection wiring line Ltest, by applying a voltage Vsel and a voltage Vdata to the third terminal Tsel and the second terminal Tdata, respectively, the input transistor Tand the output transistor Tare turned on and a current is generated in a route indicated by an arrow Rof a dotted line. Thus, the voltage Vdata is applied to the input transistor T, the inspection wiring line Ltest, and the output transistor Tin this order, and at least one of a voltage or a current can be measured at the first terminal Tp. In response to the measurement result, it is possible to detect whether the wiring line and the transistor of the control circuitare normal (presence or absence of defects).

6 When the inspection wiring line Ltest is used as the electrowetting device, it is desirable to cause no current flow or make the current as small as possible, and thus, the following steps may be performed.

3 3 For example, after the inspection is finished, a step (photolithography, etching, and peeling treatment) of removing the wiring line material of the inspection wiring line Ltest is performed. This step may also serve as a step of patterning the first metal layer Mand the element electrode. The disclosure is not limited to this, and the inspection wiring line Ltest may be cut by laser trimming.

8 FIG. 8 FIG. 2 2 2 1 2 2 6 is a circuit diagram for explaining an operation of the control circuitsarranged in an array. In, the inspection wiring line Ltest is added to each of the plurality of control circuits. By applying the voltage Vsel and the voltage Vdata to the third terminal Tsel and the second terminal Tdata, respectively, the input transistor Tand the output transistor Tare turned on, and a current flow along a route indicated by a route Rof a dotted line, and a current value can be measured from the first terminal Tp, and it is possible to detect whether the wiring line and the transistor of the control circuitare normal (presence or absence of defects). When the first terminal Tp is used as the electrowetting device, a power supply voltage (for example, Vdd) is supplied to the first terminal Tp.

2 By sequentially switching the third terminals Tsel and the second terminals Tdata to which the voltage Vsel and the voltage Vdata are applied, respectively, all the control circuitsarranged in an array can be sequentially inspected.

8 FIG. 2 2 2 In, the first terminal Tp is connected to all the control circuits, but for example, by providing a plurality of the first terminals Tp so as to be connected to each of all the control circuitsin each column direction, it is possible to simultaneously inspect the plurality of control circuits, and it is possible to shorten the inspection time.

9 FIG. 10 FIG. 2 2 is a circuit diagram of an equivalent circuit of a control circuitA according to a first modified example.is a circuit diagram for explaining an operation of the control circuitsA arranged in an array according to the first modified example.

9 FIG. 7 FIG. 2 8 1 b As illustrated in, the control circuitA includes, instead of the inspection wiring line Ltest described above with reference to, an inspection resistor Rtest having one end connected to the conduction terminaland the other end connected to the output node N.

8 2 1 6 b As described above, by increasing the resistance of the connection between the conduction terminalof the input transistor Tand the output node N, when used as the electrowetting device, only a current at a level that does not cause any problem in operation can flow through the inspection resistor Rtest. When used for inspection, by adjusting the voltage Vdata, a current can flow through the inspection resistor Rtest. The inspection resistor Rtest may be removed after the inspection is completed.

The resistance value of the inspection resistor Rtest can be adjusted by reducing the wiring line width, increasing the wiring line length, changing the wiring line material to a high-resistance material, or the like.

10 FIG. 2 1 2 In, by applying the voltage Vsel and the voltage Vdata to the third terminal Tsel and the second terminal Tdata, respectively, the input transistor Tand the output transistor Tare turned on, and a current flows from the second terminal Tdata to the first terminal Tp via the inspection resistor Rtest. Thus, the current value can be measured from the first terminal Tp, and it is possible to detect whether the wiring line and the transistor of the control circuitA are normal (presence or absence of defects).

11 FIG. 12 FIG. 2 2 is a circuit diagram of an equivalent circuit of a control circuitB according to a second modified example.is a circuit diagram for explaining an operation of the control circuitsB arranged in an array according to the second modified example.

11 FIG. 7 FIG. 2 8 1 b As illustrated in, the control circuitB includes, instead of the inspection wiring line Ltest described above with reference to, an inspection capacitor Ctest including one electrode connected to the conduction terminaland the other electrode connected to the output node N.

8 2 1 6 b As described above, the inspection capacitor Ctest is formed for connection between the conduction terminalof the input transistor Tand the output node N, and the capacitance value of the inspection capacitor Ctest and the frequency of the signal of the voltage Vdata are adjusted. In this way, when used as the electrowetting device, the capacitance value or the frequency is set so that no current flows through the inspection capacitor Ctest, and during inspection, the capacitance value or the frequency is set so that a current flows through the inspection capacitor Ctest. The capacitance value of the inspection capacitor Ctest can be adjusted by the size of the capacitance electrode and the thickness or the material of the insulating film between the capacitance electrodes.

12 FIG. 2 1 2 In, by applying the voltage Vsel to the third terminal Tsel and inputting the voltage signal Vdata having a predetermined frequency (a frequency that can easily pass through the inspection capacitor Ctest as compared with the holding capacitor Cs) to the second terminal Tdata, the input transistor Tand the output transistor Tare turned on, and a current flows from the second terminal Tdata to the first terminal Tp via the inspection capacitor Ctest. Thus, the current value can be measured from the first terminal Tp, and it is possible to detect whether the wiring line and the transistor of the control circuitB are normal (presence or absence of defects).

13 FIG. 14 FIG. 2 2 is a circuit diagram of an equivalent circuit of a control circuitC according to a third modified example.is a circuit diagram for explaining an operation of the control circuitsC arranged in an array according to the third modified example.

13 FIG. 7 FIG. 2 8 1 b As illustrated in, the control circuitC includes, instead of the inspection wiring line Ltest described above with reference to, an inspection transistor TRts including one conduction terminal connected to the conduction terminal, the other conduction terminal connected to the output node N, and a control terminal connected to a fifth terminal Ttest.

8 2 1 6 b As described above, by connecting the conduction terminalof the input transistor Tand the output nodes Nto each other via the inspection transistor TRts, during inspection, the inspection is performed in a state where the inspection transistor TRts is turned on, and when used as the electrowetting device, the inspection transistor TRts is turned off so that no current flows.

1 2 The inspection transistor TRts can be formed simultaneously with the output transistor Tand the input transistor T.

14 FIG. 2 1 2 In, by applying the voltage Vsel and the voltage Vdata to the third terminal Tsel and the second terminal Tdata, respectively, in a state where by applying the voltage Vtest to the fifth terminal Ttest first, the inspection transistor TRts is turned on, the input transistor Tand the output transistor Tare turned on, and a current flows from the second terminal Tdata to the first terminal Tp via the inspection transistor TRts. Thus, the current value can be measured from the first terminal Tp, and it is possible to detect whether the wiring line and the transistor of the control circuitC are normal (presence or absence of defects).

15 FIG. 16 FIG. 2 2 is a circuit diagram of an equivalent circuit of a control circuitD according to a second embodiment.is a circuit diagram for explaining an operation of the control circuitsD arranged in an array.

15 FIG. 2 2 1 2 1 2 8 2 1 1 1 a As illustrated in, the control circuitD includes the input transistor T, the output transistor T, the holding capacitor Cs, and an inspection resistor Rts (inspection circuit element). The control circuitD further includes the first terminal Tp, the second terminal Tdata, the third terminal Tsel, a fourth terminal Tcheck, and the output node N. In the control circuitD, a current corresponding to input to one conduction terminalof the input transistor Tflows to the output node Nvia the output transistor T. The inspection resistor Rts connects the fourth terminal Tcheck and the output node Nto each other.

1 2 4 5 2 By applying the voltage Vsel and the voltage Vdata to the third terminal Tsel and the second terminal Tdata, respectively, the output transistor Tand the input transistor Tare turned on. Then, by applying a voltage Vp to the first terminal Tp, a current flows through a route Rand a route R. Thus, at least one of a voltage or a current value of the fourth terminal Tcheck can be measured, and it is possible to detect whether the wiring line and the transistor of the control circuitD are normal (presence or absence of defects).

6 When used as the electrowetting device, it is necessary to cause current not to flow through the inspection resistor Rts (or make the current as small as possible). Alternatively, the inspection resistor Rts may be removed by the method described in the first embodiment.

6 2 5 5 In the case where the inspection resistor Rts is not removed, when used as the electrowetting device, it is possible to monitor a change in the current value due to the occurrence of a defect or deterioration in transistor characteristics. In particular, since the control circuitD is used in the conductive liquid, there is a possibility that a defect may occur due to damage caused by permeation of the conductive liquid, and thus, a monitoring function at the fourth terminal Tcheck is important.

16 FIG. 2 1 6 1 2 In, by applying the voltage Vsel and the voltage Vdata to the third terminal Tsel and the second terminal Tdata, respectively, while applying the voltage Vp to the first terminal Tp, the input transistor Tand the output transistor Tare turned on, a current flows through a route Rfrom the first terminal Tp to the fourth terminal Tcheck via the output transistor Tand the inspection resistor Rts, and by measuring at least one of a voltage or a current value of the fourth terminal Tcheck, it is possible to detect whether the wiring line and the transistor of the control circuitD are normal (presence or absence of defects).

2 1 By sequentially switching the third terminals Tsel and the second terminals Tdata to which the voltage Vsel and the voltage Vdata are applied, respectively, all the control circuitsD included in the circuit substrateD can be sequentially inspected.

16 FIG. 2 2 2 The fourth terminal Tcheck inis connected to the plurality of control circuitsD arranged in the column direction, but may be connected to the plurality of control circuitsD arranged in the row direction, or may be drawn out from each of the plurality of control circuitsD.

17 FIG. 18 FIG. 2 2 is a circuit diagram of an equivalent circuit of a control circuitE according to a fourth modified example.is a circuit diagram for explaining an operation of the control circuitsE arranged in an array according to the fourth modified example.

17 FIG. 15 FIG. 2 1 As illustrated in, the control circuitE includes, instead of the inspection resistor Rts described above with reference to, an inspection transistor TRmo. The inspection transistor TRmo includes one conduction terminal connected to the fourth terminal Tcheck, the other conduction terminal connected to the output node N, and a control terminal connected to the fifth terminal Ttest.

1 6 6 1 2 As described above, by providing the inspection transistor TRmo connected to the output node N, during inspection, the inspection is performed in a state where the inspection transistor TRmo is turned on by applying the voltage Vtest to the fifth terminal Ttest, and when used as the electrowetting device, the inspection transistor TRmo is turned off so that no current flows. Note that monitoring when the electrowetting deviceis used may be performed by turning on the inspection transistor TRmo. The inspection transistor TRmo can be formed simultaneously with the output transistor Tand the input transistor T.

18 FIG. 2 1 1 2 In, by applying the voltage Vsel and the voltage Vdata to the third terminal Tsel and the second terminal Tdata, respectively, while applying the voltage Vp to the first terminal Tp, the input transistor Tand the output transistor Tare turned on. By applying the voltage Vtest to the fifth terminal Ttest, the inspection transistor TRmo is turned on, and a current flows from the first terminal Tp to the fourth terminal Tcheck via the output transistor Tand the inspection transistor TRmo. By measuring at least one of a voltage or a current value of the fourth terminal Tcheck, it is possible to detect whether the wiring line and the transistor of the control circuitE are normal (presence or absence of defects).

2 1 By sequentially switching the terminals to which the voltage Vsel, the voltage Vdata and the voltage Vtest are applied, all the control circuitsE included in the circuit substrateE can be sequentially inspected.

18 FIG. 2 2 2 The fifth terminal Ttest inis connected to a plurality of the control circuitsE arranged in the row direction, but may be connected to the plurality of control circuitsE arranged in the column direction, or may be drawn out from each of the plurality of control circuitsE.

19 FIG. 20 FIG. 2 2 is a circuit diagram of an equivalent circuit of a control circuitF according to a fifth modified example.is a circuit diagram for explaining an operation of the control circuitsF arranged in an array according to the fifth modified example.

19 FIG. 15 FIG. 2 1 As illustrated in, the control circuitF includes, instead of the inspection resistor Rts described above with reference to, an inspection capacitor Cts including one electrode connected to the fourth terminal Tcheck and the other electrode connected to the output node N.

1 6 2 6 As described above, by providing the inspection capacitor Cts connected to the output node N, during inspection, the inspection is performed by applying the voltage Vp having a frequency that passes through the inspection capacitor Cts, and when used as the electrowetting device, by applying the voltage Vp having a frequency that does not pass through the inspection capacitor Cts, the control circuitF can be used as the electrowetting device. The capacitance value of the inspection capacitor Cts can be adjusted by the size of the capacitance electrode and the thickness and material of the insulating film between the capacitance electrodes.

20 FIG. 2 1 2 6 In, by applying the voltage Vsel and the voltage Vdata to the third terminal Tsel and the second terminal Tdata, respectively, the input transistor Tand the output transistor Tare turned on. By applying the voltage Vp having a frequency that passes through the inspection capacitor Cts to the first terminal Tp and measuring the current of the fourth terminal Tcheck, it is possible to detect whether the wiring line and the transistor of the control circuitF are normal (presence or absence of defects). When used as the electrowetting device, the voltage Vp having a frequency that does not pass through the inspection capacitor Cts is applied to the first terminal Tp.

21 FIG. 22 FIG. 2 2 is a circuit diagram of an equivalent circuit of a control circuitG according to a sixth modified example.is a circuit diagram for explaining an operation of the control circuitsG arranged in an array according to the sixth modified example.

21 FIG. 15 FIG. 2 17 1 As illustrated in, the control circuitG includes, instead of the inspection resistor Rts described above with reference to, the inspection capacitor Cts and the inspection transistor TRmo, a control terminalof the inspection transistor TRmo is connected to the output node Nvia the inspection capacitor Cts, one conduction terminal is connected to the fourth terminal Tcheck, and the other conduction terminal is connected to the fifth terminal Ttest.

6 2 Accordingly, not only during inspection but also when used as the electrowetting device, the inspection transistor TRmo is turned on according to the charge (voltage) accumulated in the inspection capacitor Cts. Thus, the voltage Vtest flows from the fifth terminal Ttest to the fourth terminal Tcheck, and by measuring the voltage/current value, the transistor performance and presence or absence of defects of the control circuitG may be monitored. The capacitance value of the inspection capacitor Cts can be adjusted by the size of the capacitance electrode and the thickness and material of the insulating film between the capacitance electrodes.

2 2 3 1 2 6 In contrast to the control circuitE described above, the control circuitG is configured such that all the potentials (currents) flow to the element electrodeconnected to the output node Nwithout leaking of the voltage Vp to the fourth terminal Tcheck. Thus, the configuration illustrated in the control circuitG can be driven more efficiently for current monitoring when used as the electrowetting device.

22 FIG. 2 1 17 2 In, by applying the voltage Vp to the first terminal Tp and by applying the voltage Vsel and the voltage Vdata to the third terminal Tsel and the second terminal Tdata, respectively, the input transistor Tand the output transistor Tare turned on, and the inspection capacitor Cts is charged. The potential charged in the inspection capacitor Cts is applied to the control terminalof the inspection transistor TRmo, and the inspection transistor TRmo is turned on. At this time, by applying the voltage Vtest to the fifth terminal Ttest, a current is generated in the fourth terminal Tcheck via the inspection transistor TRmo, and by measuring at least one of the voltage or the current of the fourth terminal Tcheck, it is possible to detect whether the wiring line and the transistor of the control circuitG are normal (presence or absence of defects).

22 FIG. 2 2 2 2 2 In, although the fifth terminal Ttest is connected to a plurality of the control circuitsG arranged in the row direction and the fourth terminal Tcheck is connected to the plurality of control circuitsG arranged in the column direction, the fifth terminal Ttest may be connected to the plurality of control circuitsG arranged in the column direction and the fourth terminal Tcheck may be connected to the plurality of control circuitsG arranged in the row direction. Both the fifth terminal Ttest and the fourth terminal Tcheck may be connected to the plurality of control circuitsG arranged in the row direction or the column direction.

1 1 1 2 2 2 2 1 1 8 2 1 8 2 9 1 2 2 2 8 2 7 1 1 b b a a The circuit substratesandA toC according to a first aspect of the disclosure are circuit substrates including the control circuitsandA toC each including the input transistor T, the output transistor T, the output node N, and the inspection circuit elements (the inspection wiring line Ltest, the inspection resistor Rtest, the inspection capacitor Ctest, and the inspection transistor Ttest) connected to the other conduction terminalof the input transistor Tand the output node N. The other conduction terminalof the input transistor Tis connected to the control terminalof the output transistor T. As a result, in the control circuitsandA toC, a current corresponding to input to the one conduction terminalof the input transistor Tflows to the first terminalvia the output node Nand the output transistor T.

According to the above configuration, it is possible to determine whether the control circuit is a non-defective product in the state of the circuit substrate.

1 1 1 2 2 2 In the circuit substratesandA toC according to a second aspect of the disclosure, in the first aspect, a control circuit group including a plurality of the control circuitsandA toC may be provided.

According to the above configuration, it is possible to determine whether the plurality of control circuits included in the circuit substrate are non-defective products.

1 In the circuit substrateaccording to a third aspect of the disclosure, in the first or second aspect, the inspection circuit element is preferably the inspection wiring line Ltest.

According to the above configuration, it is possible to determine whether the circuit substrate is a non-defective product with a simple configuration of the inspection wiring line.

1 In the circuit substrateA according to a fourth aspect of the disclosure, in the first or second aspect, the inspection circuit element is preferably an inspection resistor Rtest.

According to the above configuration, by increasing the resistance of the inspection wiring line, when the control circuit is actually used as the electrowetting device, a display device, or the like, only a current at a level that does not cause a problem in an operation can flow.

1 In the circuit substrateB according to a fifth aspect of the disclosure, in any one of the first to fourth aspects, the inspection circuit element is preferably the inspection capacitor Ctest.

According to the above configuration, during inspection, the inspection is performed with a signal having a frequency that passes through the inspection capacitor, and when used as the electrowetting device, the signal having a frequency that does not pass through the inspection capacitor can be used.

1 In the circuit substrateC according to a sixth aspect of the disclosure, in any one of the first to fifth aspects, the inspection circuit element is preferably the inspection transistor Ttest.

According to the above configuration, during inspection, the inspection is performed in a state where the inspection transistor is turned on, and when used as the electrowetting device, the inspection transistor is turned off so that no current flows.

1 1 1 2 2 2 9 1 1 In the circuit substratesandA toC according to a seventh aspect of the disclosure, in any one of the first to sixth aspects, the control circuitsandA toC each preferably include the holding capacitor Cs, and the control terminalof the output transistor Tand the output node Nare preferably connected to each other via the holding capacitor Cs.

According to the above configuration, the electric charge corresponding to input to the one conduction terminal of the input transistor can be held by the holding capacitor.

1 1 1 In the circuit substratesandA toC according to an eighth aspect of the disclosure, in the seventh aspect, the inspection circuit element is preferably connected to the holding capacitor Cs.

1 1 1 2 2 2 3 1 In the circuit substratesandA toC according to a ninth aspect of the disclosure, in any one of the first to eighth aspects, the control circuitsandA toC each preferably include the element electrodeconnected to the output node N.

According to the above configuration, the element electrode can be used as one of a pair of electrodes of the electrowetting device.

6 1 1 1 4 1 1 1 5 1 1 1 4 The electrowetting deviceaccording to a tenth aspect of the disclosure includes the circuit substratesandA toC according to the ninth aspect, the counter substratefacing the circuit substratesandA toC, and the conductive liquidsdisposed between the circuit substratesandA toC and the counter substrate.

According to the above configuration, it is possible to determine whether the plurality of control circuits included in the circuit substrate are non-defective products in the electrowetting device.

6 4 15 In the electrowetting deviceaccording to an eleventh aspect of the disclosure, in the tenth aspect, the counter substratepreferably includes the counter electrode (cathode electrode) facing the element electrode via the conductive liquid.

According to the above configuration, the droplet of the conductive liquid can be moved to a desired position by electrowetting.

6 8 2 5 3 15 a In the electrowetting deviceaccording to a twelfth aspect of the disclosure, in the eleventh aspect, a voltage corresponding to input to the one conduction terminalof the input transistor Tis preferably applied to the conductive liquidbetween the element electrodeand the counter electrode (cathode electrode).

According to the above configuration, the droplet of the conductive liquid can be moved to a desired position by electrowetting.

6 5 In the electrowetting deviceaccording to a thirteenth aspect of the disclosure, in the eleventh aspect, an ionic liquid or a polar liquid is used as the conductive liquid.

According to the above configuration, the droplet of the conductive liquid can be moved to a desired position by electrowetting.

1 1 1 1 6 5 2 2 2 1 1 2 2 8 2 1 1 2 2 1 a The circuit substratesD toG according to a fourteenth aspect of the disclosure are circuit substratesD toG used in the electrowetting deviceusing the conductive liquid, and include the control circuitsD toG each including the input transistor T, the output transistor T, and the output node N, in which in the control circuitsD toG, a current corresponding to input to one conduction terminalof the input transistor Tflows to the output node Nvia the output transistor T, and the control circuitsD toG each include the inspection circuit element (the inspection resistor Rts, the inspection capacitor Cts, and the inspection transistor TRts) connected to the output node Nand the terminal Tcheck.

2 2 According to the above configuration, by measuring the voltage/current value of the terminal Tcheck, it is possible to detect whether the wiring lines and transistors of the control circuitsD toG are normal (presence or absence of defects), and it is possible to monitor changes in the current values due to the occurrence of defects and degradation of TFT characteristics.

1 In the circuit substrateD according to a fifteenth aspect of the disclosure, in the fourteenth aspect, the inspection circuit element is preferably the inspection resistor Rst.

2 According to the above configuration, only by providing the inspection wiring line having a high resistance, it is possible to detect whether the wiring line and the transistor of the control circuitD are normal (presence or absence of a defect).

1 In the circuit substrateF according to a sixteenth aspect of the disclosure, in the fourteenth aspect, the inspection circuit element is preferably the inspection capacitor Cts.

According to the above configuration, during inspection, the inspection is performed with a signal having a frequency that passes through the inspection capacitor Cts, and when used as the electrowetting device, the signal having a frequency that does not pass through the inspection capacitor can be used.

1 In the circuit substrateE according to a seventeenth aspect of the disclosure, in the fourteenth aspect, the inspection circuit element is preferably the inspection transistor TRmo.

According to the above configuration, during inspection, the inspection is performed in a state where the inspection transistor TRmo is turned on, and when used as the electrowetting device, the inspection transistor TRmo is turned off so that no current flows. In addition, when monitoring the voltage/current during the use of the electrowetting device, the voltage/current can be monitored by turning on the inspection transistor TRmo.

1 1 In the circuit substrateG according to an eighteenth aspect of the disclosure, in the fourteenth aspect, the inspection circuit element preferably includes the inspection capacitor Cts and the inspection transistor TRmo, and the control terminal of the inspection transistor TRmo is preferably connected to the output node Nvia the inspection capacitor Cts.

2 According to the above configuration, not only during inspection but also when used as the electrowetting device, the inspection transistor TRmo is turned on according to the capacitance (voltage) accumulated in the inspection capacitor Cts. Thus, by measuring the voltage/current value of the terminal Tcheck, the transistor performance and the presence or absence of defects of the control circuitG can be monitored.

1 1 2 2 3 1 In the circuit substratesD toG according to a nineteenth aspect of the disclosure, in any one of the fourteenth to eighteenth aspects, the control circuitsD toG each preferably include the element electrodeconnected to the output node N.

6 1 1 4 1 1 5 1 1 4 The electrowetting deviceaccording to a twentieth aspect of the disclosure includes the circuit substratesD toG according to the nineteenth aspect, the counter substratefacing the circuit substratesD toG, and the conductive liquidsdisposed between the circuit substratesD toG and the counter substrate.

The disclosure is not limited to the embodiments described above, and various modifications may be made within the scope of the claims. Embodiments obtained by appropriately combining technical approaches disclosed in the different embodiments also fall within the technical scope of the disclosure. Furthermore, novel technical features can be formed by combining the technical approaches disclosed in the embodiments.

While preferred embodiments of the present invention have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the present invention. The scope of the present invention, therefore, is to be determined solely by the following claims.